Hydrophobic coatings and synthesis by electrochemical reduction of sulfonium compounds

ABSTRACT

Nonpolymeric hydrophobic coatings are applied to solid electroconductive articles used as cathodes in an electrolysis system by subjecting a solution of a sulfonium salt in a predominantly aqueous electrolysis solvent to an electrical potential sufficient to reduce the sulfonium salt. Water is the preferred solvent. In example, iron is coated with a grease by the electrochemical reduction of p-dodecylbenzyldimethylsulfonium chloride in aqueous solution at a cathode potential (reducing potential) of -1.0 volts versus a standard calomel electrode; the grease being a mixture of p,p&#39;&#39;-bis(dodecyl)bibenzyl and pdodecyltoluene.

United States Patent [191 Settineri et al.

[ Dec. 3, 1974 [75] Inventors: William J. Settineri; Ritchie A.

Wessling, both of Midland, Mich.

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

[22] Filed: Sept. 26, 1972 2 11 Appl. No.: 292,292

Related US Application Data [63] Continuation-impart of Serv No.879,511, Nov. 24, 1969, abandoned, which is a continuation-in-part ofSer. Nos. 647,895, June 22, 1967, Pat. No. 3,480,525, and Ser. No.647,896, June 22, 1967, Pat.

[52] US. Cl 204/73 R [51] Int. Cl. C07b 19/06, BOlk 1/00, C231 7/00 [58]Field of Search 204/73 R [56] References Cited UNITED STATES PATENTS3,480,527 11/1969 Wessling et a1. 204/73 R Settineri et a1. 204/72Wessling et a1 204/72 Primary ExaminerF. C. Edmundson Attorney, Agent,or Firm-L. Wayne White ABSTRACT Nonpolymeric hydrophobic coatings areapplied to solid electroconductive articles used as cathodes in anelectrolysis system by subjecting a solution of a sulfonium salt in apredominantly aqueous electrolysis solvent to an electrical potentialsufficient to reduce the sulfonium salt. Water is the preferred solvent.ln example, iron is coated with a grease by the electrochemicalreduction of p-dodecylbenzyldimethylsulfonium chloride in aqueoussolution at a cathode potential (reducing potential) of 1.0 volts versusa standard calomel electrode; the grease being a mixture ofp,p-bis(dodecyl)bibenzyl and p-dodecyltoluene.

26 Claims, No Drawings HYDROPHOBIC COATINGS AND SYNTHESIS BYELECTROCHEMICAL REDUCTION OF SULFONIUM COMPOUNDS CROSS-REFERENCE TORELATED APPLICATIONS This application is a continuation-in-part of ourcopending U.S. Pat. Application, Ser. No. 879,511 filed Nov. 24, 1969,now abandoned which in turn is a continuation-in-part of our copendingU.S. Patent Applications, Ser. Nos. 647,895 and 647,896, filed June 22,1967, now U.S. Pat. Nos. 3,480,525 and 3,480,527, respectively.

BACKGROUND OF THE INVENTION Polarography is a well established means ofquantitatively identifying various electroreducible components in amixture, such as the identification of each metal in a mixture of metalsalts. See, for example, Polarographic Techniques, by L. Meites, 2ndEd., John Wiley and Sons, Inc. (1965).

Analytical polarographic techniques generally require a mercury orplatinum cathode, mercury electrodes being by far the most common, andextremely well controlled electrical potentials. See L. Meites,Controlled-Potential Electrolysis in A. Weissberger, Editor, Techniqueof Organic Chemistry, Vol. 1, 3rd Edition (lnterscience, N.Y., 1959 pp.3281-3333, for a general summary.

The polarography of certain sulfonium s'alts is described by Colichmanand Love, J. Org. Chem., 18, 40 (1953). However, the production of anyuseful material by the electroreduction of sulfonium salts was unknownuntil we discovered that p,p-dinitrobibenzyl compounds andpoly(p-xylylene) could be-prepared by the electrochemical reduction ofthe appropriate sulfonium salts, described in our copending patentapplica tions Ser. Nos. 647,896 and 647,895, which are now U.S. Pat.Nos. 3,480,527 and 3,480,525, respectively.

SUMMARY OF THE INVENTION This invention pertains to our furtherdiscoveries regarding the electrochemical reduction of organic sulfoniumsalts; said reduction requiring an electrolysis system comprising ananode, a cathode, an electrolysis solvent and a means for establishingand maintaining an electrical potential between said anode and cathode.

It has now been discovered that solid electroconductive articles can beeasily coated with a uniform hydrophobic coating by using suchelectroconductive articles as the cathode in the above-describedelectrolysis system and subjecting a solution of an organicmonosulfonium salt and an electrolysis solvent to an electricalpotential sufficient to reduce said sulfonium salt. Thewear-resistantcoating, or one can apply a decorative and/or colored coating to variousarticles (color being imparted by a chromophore(s) in the product), andother like uses. The major import of this aspect of the subjectinvention resides in coating metals, particularly iron and copper andtheir alloys with a protective and- /or lubricating coating byelectrochemically reducing a sulfonium salt from an aqueous solution.

Another important aspect of this invention is that the coatings thusproduced are due to and accompanied by the one-step electrochemicalsynthesis of many useful compounds. Such compounds may be recovered fromthe reaction mixture by washing the cathode with an appropriate solvent,scraping or wiping the cathode, by choosing an electrolysis solventwhich dissolves both the sulfonium reactant and the product(s) thusproduced or by any other convenient method.

Generally, the coating is a mixture of compounds. E.g., the electrolysisof benzyldimethylsulfonium chloride in aqueous solution produces (a)bibenzyl, (b) toluene and (c) dimethylsulfide. The product distributionof (a) to (b) within the mixture can be varied by the choice ofsulfonium salt(s) and process conditions.

The electrochemical preparation of p,pdinitrobibenzyl compounds fromp-nitrobenzyl sulfonium salts was described in our copending application(Ser. No. 647,896), which illustrates the coupling reaction. Thesynthesis was conducted in an aqueous or polar organic solvent usingmercury, platinum or copper and other electroconductive materials, suchas graphite, as the cathode.

The dimerization of p-nitrobenzyl sulfonium salts is facilitated by thep-nitro substituent group which has a relatively high Hammett 0'constant reflecting a high I (r values of the substituent groups. But,in view of the relation shown by Streitweiser, it was not surprising todiscover that benzylic sulfonium salt did not follow such a reasonablylinear relationship and that benzylic sulfonium salts bearingpara-substituents having a relatively low or even negative 0 value, suchas dodecyl, could be electrochemically reduced and undergo acorresponding coupling reaction at surprisingly low cathode potentials(reducing potentials) in corresponding solvents (particularly water).From'Streitweiser, one would have predicted that benzylic sulfoniumsalts having substituents with a low or negative oconst'ant would haverequired much higher cathode potentials, i.e., increasingly negativevoltages, than was actually observed and in those instances where thesubstituent had a 0' constant as negative as dodecyl, for example, theelectrolytic decomposition of water would have been expected on cathodeshaving a low hydrogen overvolt- 1 age, such as platinum. This was notobserved to any substantial degree. A similar case of reduction isexperienced for other sulfonium salts as described herein The'cathodemay suitably be any article which is solid and electroconductive and maybe metallic or nonmetallic in nature. Illustrative of suitable cathodesare (a) articles of metals having a hydrogen overvoltage less thanmercury, such as those having a relatively low hydrogen overvoltage(e.g., iron, nickel and platinum) and those having a relatively highhydrogen overvoltage (e.g.,.lead, copper and tin), and metal alloys,such as steel, brass, and the like, and articles bearing a conductivemetal coating, such as chromeor copperplated iron or steel articles,aluminumor chromeplated plastic articles, and the like, and (b)nonmetallic articles, made from carbon, graphite and the like and otherelectrical semiconductors, such as gallium, germanium, and the like. Itis known that most metals are electroconductive and have a resistivityof less than about ohm-cm. at 300 K. and that most electricalsemiconductors have a resistivity of less than about 10 ohm-cm. at 300K. Conductor metals are the preferred class of materialsto be coated,particularly iron, copper, nickel, aluminum, tin, zinc, lead and alloysthereof, based on the extensive commercial use of such metals. The mostpreferred metals being iron, copper or alloys of iron or copper.

The shape and size of the article to be coated is relativelyunimportant. E.g., needles, razor blades, transistors, diodes, tubes,wire, barrels, car bodies, pipelines, etc.', on up to a slab of rolledmetal can be coated by the subject process. This fact makes theinvention particularly useful since there -is a tremendous need forprotective coatings, and a method of applying same, on articles whichare subject to oxidation and degradation when exposed to the atmosphere,such as an unpainted car body, particularly temporary coatings which canbe easily removed with a solvent. The process may be used to applyinsulating coatings to electrical wire and parts. The subject processmay be used to coat rough surfaces as well as smooth, although forpractical reasons, smooth regular surfaces are preferred when thepurpose is to prepare and recover the electrolysis product. B. THESULFONIUM SALTS Suitable sulfonium salts have the formula ia a? n-C Hwherein R R and R are hydrocarbon 0r hydroxy. halo-, nitroorcyano-substituted hydrocarbon groups having up to about 30 carbon atomsor more and are limited only by the solubility of the sulfonium salt inthe electrolysis solvent, and A is an electrolytically acceptable anion,such as an anion of an inorganic or organic acid. Preferred salts arethose wherein R and R are lower alkyl or hydroxy-alkyl of 1' to about 10carbon atoms and R is an activated group; by activated" we mean a grouphaving a methylene. carbon attached to the sulfonium sulfur and which isactivated by being attached to an aromatic nucleus, a carbonyl group, anolefin or other like groups. Preferred R groups therefore include abenzyl group having the formula (v) CH2 wherein R is a hydrocarbongroup, such as alkyl, aryl, aralkyl, alkaryl, cycloaliphatic alkenyl ora corresponding halo-substituted hydrocarbon group and n is an integer 0to 5. Most preferably, R and R are alkyl groups of one to about fourcarbon atoms and R is a benzyl group having the formula 'wherein R ishydrogen, alkyl (particularly alkyl of 4 to 18 carbon atoms) or alkenyl(particularly vinyl or allyl); an allyl group (CH #IHCH an ester oramide group wherein R is alkyl, aryl, etc.) and other like groups.Examples of suitable such sulfonium salts include those of the FormulaIV wherein:

Table I a a CH CH C1 n-cglt n-CnH Br 0 5 C H Br n-.G1;H OH n-QuH OH Fcan on c n on c1 ri -emu? M 311 (:1 CH CH atzggyl CH C 11 N0 Table IContinued cH (-ca SQ on Dian -O c a swa 3 or s-c a and the like Asabove, the electrolysis process-results in a mixture of products whichmay be represented by R R R -H and R -SR (R naturally could be replaced5 with R and R If R, through R are each low molecular weight groups (oneto about five carbon atoms), then the product is generally a mixture ofgases or liquids having a specific gravity less than one-hence,

such sulfonium salts are not particularly useful in ap- I plying aprotective or lubricating coating per se, but they are operable in theprocess for synthesizing certain compounds. Furthermore, the volatilityof the R S-R by-product when R and R are of low molecular weights can beused to advantage when a sulfide is not desirable in the end product;and the converse when R SR is a desirable component, such as tolylnte(cHFcm-cu-r cH 'hs which is hydrophobic and can be subsequently cured togive a hard coating.

C. THE SOLVENT Suitable electrolysis solvents are compounds whichdissolve the sulfonium salts and are inert to the product formed.Suitable solvents therefore include water,

polar organic solvents, such as tetrahydrofuran, dimethylformamide,dioxane, acetonitrile, propionitrile, dimethylsulfoxide, hexamethylphosphoramide, lower alkanols, such as methanol, ethanol, isopropanoland 'butanol, organic acids, mixtures of the above organic solvents,mixtures of the above organic solvents and water, and the like.Preferred solvents when a coating is desired are those which dissolvethe salt but which do not dissolve, delaminate or otherwise adverselyaffect the coating formed; such solvents arepredominantly water. Wateris the most preferred solvent in coating applications, said preferencebeing based on' its excellent solvating properties for most sulfoniumsalts (and supporting electrolytes, if used), its ready availability,ease of handling, etc.

D. VOLTAGE The voltage and current requirement through the electrolyticmedia depend on the particular sulfonium salt to be reduced; however,any voltage and amperage sufficient to reduce said salt is suitable solong as the electrolysis solvent is not correspondingly orpreferentially reduced since degradation of the solvent may causeirregularities in the desired hydrophobic coating. Voltage levels whichreduce both the sulfonium salt and solvent are operable but notpreferred. The electrical potential (reducing voltage) may be appliedand maintained at a constant value by continuously decreasing theapplied voltage, as described by Meites above, or a potential may besupplied from a constant energy source, such as a battery. In the latterinstance,

the measured electrical potential at the cathode would decrease to amore negative value as the cathode is coated. Both methods of applyingthe electrical potential have many advantages, however, we currentlyprefer the controlled voltage technique since little, if any, gassing isgenerally observed. E. SUPPORTING ELECTROLYTES The subject process mayoptionally include a supporting electrolyte, such as salts of strongacids, in the electrolysis solvent media. Examples of such supportingelectrolytes include NaCl, KCl, NaNO Na- SO and the like. The use ofsuch salts does not hinder the formation of the desired coating so longas the electrical potential is insufficient to reduce the metal cations.Use of such salts may be advantageous in assisting'the flow of currentthrough the reaction mixture and thereby hasten the desired reaction.However, the use of supporting electrolytes is not required and isundesirable when the supporting electrolyte may corrode the electrode.E.g., KCl entrained in the coating of steel article may eventually causecorrosion. .ELQED ERA PROCESS NDIT QNS The subject process may beconducted as a batch or continuous process, i.e., the electrolyte media,comprising an electrolysis solvent and organic sulfonium salt, may becontinuously rejuvenated by adding in (a) more sulfonium salt or (b) areactant, such as benzyl chloride, which reacts with the sulfidely-Product to form the sulfonium salt in situ. Additionally, the cathodemay be a single item to be coated or a series of such items which can beremoved en masse or individually. The concentration of the sulfoniumsalt in the electrolysis solvent is not critical. However, a sufficient.

9 surface. This drift does in some instances result in hydrogen bubblesbeing evolved (gassing) when water is ferred in some instances tominimize the formation of hydrogen gas.

SPECIFIC EMBODIMENTS The following examples further illustrate theinvention:

Unless otherwise stated, the electroylysis solvent is water, the cathodepotential is expressed in volts in comparison with a saturated calomelelectrode (SCE),

and the anode is a carbon or graphite rod.

Example l I Preparation and Coating of Bibenzyl on a Platinum CathodeThe technique of controlled-potential electrolysis is explained indetail in Meites, Controlled Potential Electrolysis in A. WeissbergerEditor, Technique of Organic Chemistry, Vol. 1, 3rd. Edition(lnterscience, New York, 1959, pages 328l3333). This technique and athree-compartment glass electrolysis cell as described by Meites wasemployed for the electroreduction. A platinum cathode and graphite anodewere used, and a magnetic stirring bar was used to agitate thecatholyte. The cathode compartment contained 7.7 X 10 moles ofbenzyldimethylsulfonium tosylate (m.p. l24-125C.) and approximately 200ml. of 0.2 N tetraethylammonium bromide (TEAB) in dimethylformamide(DMF). The central and anode compartments contained only 0.2 N TEAB inDMF solution. The reducing potential-at the platinum cathode wasmaintained at l .1 volts versus the SCE. The reduction was carried outat room temperature and the cathode compartrnent was continuouslyflushed with nitrogen. Initial current was 42 milliamperes (ma) and thisdropped to about 0.2 ma. in the course of the reduction which was about12 hours. The resulting DMF solution in the cathode compartment wasanalyzed for bibenzyl by vapor phase chromatography (VPC) and massspectrometry. Measured yield of bibenzyl by VPC was percent of originalsulfonium compound used.

In a similar experiment, water replaced DMF as the electrolysis solventand bibenzyl coated the cathode. The coating was removable by washingthe coated cathode with DMF or other organic solvents.

Similar results were obtained by using an aqueous solution of thetosylate and replacing the platinum cathode with a steel (ca. 1 in.surface). The reduction was carried out at -l .25 volts vs. SCE; currentranged from 20 ma. to 34 ma. over a 2 minute time interval. Bibenzylcoated the steel chip.

Example 2 g Preparation and Coating of p,p'-Dichlorobibenzyl Thisexample utilizes the technique of uncontrolled potential electrolysis.In this technique, the applied potential (driving potential) is' set ata constant value and the cathode potential (reducing potential) isuncontrolled, i.e., it is allowed to drift to increasingly negativevalues as the sulfonium reactant is depleted and/or anelectrically-resistant coating is formed on the cathode the electrolysissolvent. The electrolysis cell is a threecompartment glass cell in whichthe cathode compartment was separated from the anode compartment by acentral compartment and porous glass frits. The anode was a carbon rod.The anode and central compartments were filled with a 0.5 N aqueous KClsolution.

The reaction temperature was 25C. The cathode com-- partment was filledwith 200 ml. of a 0.5 N aqueous solution ofp-chlorobenzyldimethylsulfonium chloride. A driving voltage of 3 to 5volts was applied and the reduction occurred using various metals ascathodes (surface area E 1.5 in. The results are summarized in Table II.

ma. milliampercs In all examples,

In each instance, some gassing was observed and the crystalline coatingwas identified as p,pdichlorobibenzyl (m.p., 8995C.). Example 3Preparation and Coating of 2,2,4,4'-Tetrachlorobibenzyl Using theuncontrolled potential technique and general procedure set forth inExampleZ, except for the sulfonium salt and catholyte concentration, thefollowing runs were made using a 0.3 N aqueous solution of2,4-dichloi'obenzyldimethylsulfonium chloride and several types ofcathodes. Unless otherwise noted, all cathodes had about 1 square inchof surface area; reaction times were four minutes.

' four wires (1.009" in diameter l inch long "wire 0.125" in diameter a1 inch long In two similar experiments, except for the applied voltages,two steel cathodes were coated as follows:

Table IV Driving Initial Potential Current Initial Cathode No. (Volts)(ma.) Potential (Volts) l6 I I00 I7 30 400 6 No gassing was observed inRun 16 for 30 seconds, after which a small amount did occur. Run 17,gassing occurred immediately in large quantitiesa In four other similarruns, except that controlledpotential electrolysis technique replacedthe uncontrolled electrolysis technique, various cathodes were coated asfollows:

Table V Cathode Cathode Potential Current (ma.) Time No. Metal (Volts)Initial Final (min.)

l8 steel O.9 40 6.5 5 l9 platinum 0.7 20 5 5 20 copper .3 25 2 4 21aluminum l.) 20 35 10 Some gassing was observed in Run 21 but not in18-20.

In every instance above, 2,2,4,4'-tetrachlorobibenzyl coated the cathodesurface; the product was a white crystalline solid; m.p., to C.

Example 4 Preparation and Coating of p,p-Difluorobibenzyl Using theuncontrolledpotential technique and general procedure set forth inExample 2, a 0.25 N aqueous solution of p-fluorobenzyldimethylsulfoniumchloride (no KCl in catholyte) was electrolyzed under the followingconditions: I

Table VI Initial Cathode Initial Cathode Potential Current Time No.Metal (Volts) (mat) (min.)

1 steel -096 l0 l5 '2 copper l.l 10 15 In both instances, the cathodewas coated with p,pdifluorobibenzyl and no gassing was observed. Example5 Preparation and Coating of p,p'-Dinitrobibenzyl An aqueous solution0.04 N in p-nitrobenzyldimethylsulfonium chloride and 0.5 N in KC] wasplaced in a beaker equipped .with a carbon rod anode and a copper orplatinum cathode. An electrical potential was applied such that thecathode potential was between 0.6 and -O.8 volts vs SCE. A yellowcrystalline compound coated the surface of the cathode. The compound wasidentified as p,p-dinitrobibenzyl. Example 6 I 7 Preparation and Coatingof p,p'-Bis(t-Amyl)- Bibenzyl I Using the controlled-potentialelectrolysis technique as in Example 1, the electrolysis cell was filledwith a 0.3 N aqueous KC] solution and the catholyte was additionallymade 0.1 N in p-t-amylbenzyldimethylsulfonium chloride. A carbon anodeand steel cathode (l in?) was used. The solution was electrolyzed for 2min. at 25C. under a cathode potential of l .3 volts during which timethe current decayed from 40 to 2 ma. The powdery white coating wasidentified as a mixture containing a major proportion ofp,p-bis(t-amyl)bibenzyl and a minor amount of p-t-amyltoluene. Example 7Preparation and Coating of p,p-Bis(Dodecyl) Bibenzyl Using theuncontrolled potential technique and general procedure as set forth inExample 2, except that no supporting electrolyte was used in thecatholyte, a 0.215 N aqueous solution of palkylbenzyldimethylsulfoniumchloride was electrolyzed for minuets under the following conditions:

Catholyte was 0.5 N in KCl "Reaction time was 15 min.

In each instance, the cathode was coated with a mixture ofp,p-bis(alkyl)bibenzyl and p-alkyltoluene, The alkyl substituent was amixture of C to C alkyl groups with an average of C The producttherefore contained a random mixture of bis(C to C substituted bibenzyland p-(C to C )-toluene, e.g., 12 2S' 6 4 2 2 6 4 12 25a 12 2s s- H CHCH C H C H etc. The coating afforded excellent rust protection for thesteel and iron cathodes no rust was. observed on the coated portion evenafter 2 days in Water while severe rusting was observed on the uncoatedportion (portion held above the catholyte during electrolysis). Example8 Preparation and Coating of p,p-Divinylbenzyl Using the uncontrolledpotential technique and the general procedure set forth in Example 2,except for the sulfonium salt and c'atholyte concentration, a 0.3 Naqueous solution of p-vinylbenzyldimethylsulfonium nitrate waselectrolyzed for 45 minutes under the following conditions:

Table Vlll Cathode Cathode Potential lnitial No. Material (Volts)Current (ma.) Gassing 1 steel 'l.1 15 no 2 stainless 1.3 20 yes steel 3phosph ated l .4 15 yes steel 4 iron wire -l.2 15 no 5 platinum -l.0 15very little I 6 copper --l.() 15 no 7 aluminum 1 .9 15 yes 8 aluminum*1.5 15 yes 9 molybdenum l.4 15 yes 10 tin l.5 yes 1 l zinc l .5 no i2silver wire -l.5. 7 15 no 13 lead l.0 15 no 14 magnesium -l.9 l0 yes 15titanium -l .5 17 yes 16 graphite l .3 15 no Freshly polished with steelwool other aluminum cathode-merely cleaned with solvent,

More gassing was observed on magnesium than for any other metal.

In each instance the coating was identified as p,p divinylbibenzyl. Thecoated cathodes were subsequently removed and heated at C. for 12 hours.The coating thus obtained was a hard, clear, seemingly col orlesspolymer film which provided amazingly good rust protection for the steeland iron articles and good protection against oxidation for metals, suchas copper, even when stored in an air oven for 48 hours at C.

In this experiment, as in substantially all of the examples presentedherein, the coating was noted to give. similar protection to the edges,corners and rough surfaces as well asto the smooth flat surfaces. Theuncured coating was easily removed by washing the surface with CClExample 9 Preparation and Coating of a,a'-Dimethylbibenzyl Using thecontrolled-potential electrolysis technique and procedures as set forthin Example 1, ml. of 0.5 N tetraethylammonium tosylate (TEAT) indimethylformamide (DMF) containing 0.0099 moles ofa-methylbenzyldimethylammonium tosylate (mp, l 10l 13C.) waselectrolyzed at a cathode potential of l.2 volts for 24 hours at 25C.during which time the current decayed from 62 to 0.2 ma. The center andanode compartments contained 0.5 N TEAT in DMF and the anode wasgraphite. The DMF soluble product was identified asa,a'-dimethylbibenzyl; product yield was 90 percent. Similar results areobtained by replacing DMF with water or ethanol-water mixtures exceptthat the product coats the cathode. A lead cathode was used.

Example 10 Preparation and Coating of n-Octane Using the uncontrolledpotential technique and general procedure set forth in Example 2, exceptfor the sulfonium salt and catholyte concentration, a 0.1 N aqueoussolution of n-octyldimet hylsulfonium nitrate was electrolyzed using asteel cathode. Several runs were conducted at cathode potentials betweenO.5 and 1.1 volts and in each instance the current quickly decayed tozero. The cathode potential also drifted in each instance to morenegative values, indicating good cathode coverage by a resistantcoating. At cathode potentials of l .3 to l.5 volts, the currentremained essentially constant at 15 ma; slight gassing was observed. Thecathode was withdrawn and the oily coating analyzed by massspectroscopy; n-octane was identified as the major product. Similarresults were obtained by using a lead cathode, Example 11 Using theuncontrolled potential technique and general procedure setforth'inExample 2, except for the sulfonium salt and catholyteconcentration, a 0.2 N aqueous solution of (no KCl in catholyte) waselectrolyzed in three separate runs using various cathodes (surface areaof each was ca. 1.5 inf).

' Table 1X Several runs were made using various cathodes and 2 minutereaction times. The results are tabulated in Table X:

Table X Initial Cathode lnitial Cathode Current No. Material Potential(Volts) (ma.) Gassing 1 steel l.05 yes 2 lead l.2 no 3 platinum ().5 15yes 4 copper ().7 15 yes The oily coatings thus produced were found tobe a mixture of p-hydroxyphenyl n-butyl sulfide and the coupled product(HOC H.,S+CH Gil -r Similar results are obtained using other sulfoniumsalts, other solvents, other materials as cathodes and at voltages andamperages as described herein.

The coatings as illustrated above and those produced by using othersulfonium reactants as described herein are useful as protective orlubricating coatings, as electrical insulators, and other like uses.

Example 13 Using the controlled-potential electrolysis technique andgeneral procedure set forth in Example 1, a 0.5 N aqueous KCl solutioncontaining triphenylsulfonium chloride (10 g./200 ml.) waselectrolyzedusing various metal cathodes. The results are summarized inTable XI.

Table X1 Cathode Cathode Initial No. Metal Potential (Volts) Current(ma.) Gassing '1 steel 1 .4 16 yes 2 platinum l.45 7.6 yes 3 copper 1.814 yes The products were biphenyl and phenyl sulfide. Example 14 Usingthe uncontrolled potential and general procedure set forth in Example 2,0.6 N aqueous solution (no KCI) of a resistivity of less than about 10ohm-cm. at 300 K. and being used as a cathode in a system comprising ananode, a cathode, an aqueous electrolysis solvent which is predominantlywater and a means for applying and maintaining an electrical potentialbetween said anode and cathode, said process comprising subjecting asolution of an organic monosulfonium salt in said aqueous electrolysissolvent to an electrical potential sufficient to reduce said salt; saidhydrophobic coating being substantially insoluble in said electrolysissolvent.

2. The process defined in claim 1 wherein said electrolysis solvent iswater.

3. The process defined in claim 1 wherein said cath- 4 ode is aconductor metal having a resistivity of less than R1 AG 5 wherein R Rand R are hydrocarbon or halo-, hy-

droxyor cyano-substituted hydrocarbon groups having up to 30 carbonatoms, and A is an electrolytically acceptable anion. v

6. The process defined in claim 5 wherein R and R are each lower alkylor hydroxyalkyl of one to four car bon atoms.

7. The process defined in claim 6 wherein R has the formula wherein n isan integer from O to 5, and R is an alkyl, aryl, aralkyl, alkaryl,cycloalkyl or alkenyl group or corresponding halo-substituted group. ,8.The process defined in claim 7 wherein n is l and R is alkyl, alkenyl,or an ester or amide group of the formula defined by claim 5.

14. The coatedproduct according to claim 9, the

coating of which is subsequently cured.

15. The process as defined in claim 1 wherein said electrical potentialis maintained at a substantially constant value.

16. A process for preparing a compound of the for-' rnula R H or R Rcomprising subjecting an or-' garric sulfonium salt in an electrolysissolvent to an electrical potential sufficient to reduce said sulfoniumsalt; said salt having the formula 23. The process defined in claim 1wherein said solution is stirred during the process.

24. The process defined in claim 3 wherein said cathode is iron, steel,copper, platinum, silver, aluminum,

Q 5 molybdenumflin, zinc, lead, magnesium or titanium, R1 S B2 A andwherein said organic monosulfonium salt is i benzyldimethylsulfoniumtosylate, 4- R chlorobenzyldimethylsulfonium chloride, 2,4-dichlorobenzyldimethylsulfonium chloride, 4- 1ofluorobenzyldimethylsulfonium chloride, 4- wherein R R and R arehydrocarbon or halo-, hynitrobenzyldimethylsulfonium chloride,4-tdroxyor cyano-substituted hydrocarbon groupshavamylbenzyldimethylsulfoniurn chloride, 4- ing up to 30 carbon atoms;said process being conalkylbenzyldimethylsulfonium chloride wherein saidducted in an electrolysis system comprising an anode, alkyl substituentis from a C to C alkyl group, 4- a cathode, an electrolysis solvent anda means for ap- 15 vinylbenzyldimethylsulfonium nitrate, plying andmaintaining an electrical potential betweena-methylbenzyldimethylsulfonium tosylate, said anode and cathode.n-octyldimethylsulfonium nitrate,

e '7 1 e w e e w e29 G E 6-GE 3%W I E 17. The process defined in claim 9wherein R isvinyl or ailyl.

18. The process defined in claim 17 wherein the hydrophobic coating thusobtained is subsequently cured.

19. The coated product produced by the process as defined by claim 18.

20. The process defined by claim 3 wherein said cathode is iron, copper,nickel, aluminum, tin, zinc, lead, or an alloy thereof.

21. The process defined in claim 4 wherein said cathode is iron or analloy thereof.

22. The process defined in claim wherein R is an activated hydrocarbonor halo-, hydroxyor cyanosubstituted hydrocarbon group, and R and R arealkyl or hydroxyalkyl groups of from 1 to carbon atoms.

triphenylsulfonium chloride or UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION PATENT NO. 3,852,174 DATED December 3, 1974 |NVENTOR(S) 3William J. Settineri and Ritchie A. Wessling it is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Column 2, line 38: "not" should be most.

Column 2, line 48: o"constant should be 0' constant.

Column 11, line 65: "along" should be long.

Signed and Sealed this twenty-ninth Day of July 1975 [SEAL] A ttes I:

RUTH C. MASON C. MARSHALL DANN Alresring Officer ('ummr'ssr'mu'rujlure'nm and Trademarks

1. A PROCESS FOR APPLYING A NONPOLYMERIC HYDROPHOBIC COATING TO A SOLIDELECTROCONDUCTIVE ARTICLE HAVING A RESISTIVITY OF LESS THAN ABOUT 10**8OHM-CM. AT 300*K. AND BEING USED AS A CATHODE IN A SYSTEM COMPRISING ANANODE, A CATHODE, AN AQUEOUS ELECTROLYSIS SOLVENT WHICH IS PREDOMINANTLYWATER AND A MEANS FOR APPLYING AND MAINTAINING AN ELECTRICAL POTENTIALBETWEEN SAID ANODE AND CATHODE, SAID PROCESS COMPRISING SUBJECTING ASOLUTION OF AN ORGANIC MONOSULFONIUM SALT IN SAID AQUEOUS ELECTROLYSISSOLVENT TO AN ELECTRICAL POTENTIAL SUFFICIENT TO REDUCE SAID SALT; SAIDHYDROPHOBIC COATING BEING SUBSTANTIALLY INSOLUBLE IN SAID ELECTROLYSISSOLVENT.
 2. The process defined in claim 1 wherein said electrolysissolvent is water.
 3. The process defined in claim 1 wherein said cathodeis a conductor metal having a resistivity of less than about 10 2ohm-cm. at 300* K.
 4. The process defined in claim 3 wherein saidcathode is iron, copper, or an alloy thereof.
 5. The process defined inclaim 1 wherein said sulfonium salt has the formula
 6. The processdefined in claim 5 wherein R2 and R3 are each lower alkyl orhydroxyalkyl of one to four carbon atoms.
 7. The process defined inclaim 6 wherein R1 has the formula
 8. The process defined in claim 7wherein n is 1 and R4 is alkyl, alkenyl, or an ester or amide group ofthe formula
 9. The process defined in claim 8 wherein R4 is alkyl of 4to 18 carbon atoms or vinyl or allyl.
 10. The process defined in claim 5wherein said electrolysis solvent is water.
 11. The coated productproduced by the process as defined by claim
 1. 12. The coated metalproduct produced by the process as defined by claim
 3. 13. The coatedproduct produced by the process as defined by claim
 5. 14. The coatedproduct according to claim 9, the coating of which is subsequentlycured.
 15. The process as defined in claim 1 wherein said electricalpotential is maintained at a substantially constant value.
 16. A processfor preparing a compound of the formula R1-H or R1-R1 comprisingsubjecting an organic sulfonium salt in an electrolysis solvent to anelectrical potential sufficient to reduce said sulfonium salt; said salthaving the formula
 17. The process defined in claim 9 wherein R4 isvinyl or allyl.
 18. The process defined in claim 17 wherein thehydrophobic coating thus obtained is subsequently cured.
 19. The coatedproduct produced by the process as defined by claim
 18. 20. The processdefined by claim 3 wherein said cathode is iron, copper, nickel,aluminum, tin, zinc, lead, or an alloy thereof.
 21. The process definedin claim 4 wherein said cathode is iron or an alloy thereof.
 22. Theprocess defined in claim 5 wherein R1 is an activated hydrocarbon orhalo-, hydroxy- or cyano-substituted hydrocarbon group, and R2 and R3are alkyl or hydroxyalkyl groups of from 1 to 10 carbon atoms.
 23. Theprocess defined in claim 1 wherein said solution is stirred during theprocess.
 24. The process defined in claim 3 wherein said cathode isiron, steel, copper, platinum, silver, aluminum, molybdenum, tin, zinc,lead, magnesium or titanium; and wherein said organic monosulfonium saltis benzyldimethylsulfonium tosylate, 4-chlorobenzyldimethylsulfoniumchloride, 2,4-dichlorobenzyldimethylsulfonium chloride,4-fluorobenzyldimethylsulfonium chloride, 4-nitrobenzyldimethylsulfoniumchloride, 4-t-amylbenzyldimethylsulfonium chloride,4-alkylBenzyldimethylsulfonium chloride wherein said alkyl substituentis from a C8 to C18 alkyl group, 4-vinylbenzyldimethylsulfonium nitrate,Alpha -methylbenzyldimethylsulfonium tosylate, n-octyldimethylsulfoniumnitrate,
 25. The process defined by claim 1 with the provision that saidorganic monosulfonium salt is not a nitrobenzyl dialkyl ordihydroxyalkyl sulfonium salt or a nitrobenzyl alkyl hydroxyalkylsulfonium salt.
 26. The product produced by the process defined by claim25.